[SCSI] qla2xxx: Correct extended sense-data handling.

Earlier implementation did not take into account the varying
sizes of data buffers returned from structures sts_entry_t and
sts_entry_24xx.  Sense-data after the 20th byte could be
incorrect.

Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>